usb: typec: add support for the nb7vpq904m Type-C Linear Redriver

Add support for the ON Semiconductor NB7VPQ904M Type-C USB SuperSpeed
and DisplayPort ALT Mode Linear Redriver chip found on some devices
with a Type-C port.

The redriver compensates ultra High-Speeed DisplayPort and USB
Super Speed signal integrity losses mainly due to PCB & transmission
cables.

The redriver doesn't support SuperSpeed lines swapping, but
can support Type-C SBU lines swapping.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Message-ID: <20230601-topic-sm8x50-upstream-redriver-v4-2-91d5820f3a03@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 538 insertions, 0 deletions

diff --git a/drivers/usb/typec/mux/Kconfig b/drivers/usb/typec/mux/Kconfig
index c46fa4f9d3df..8c4d6b8fb75c 100644
--- a/drivers/usb/typec/mux/Kconfig
+++ b/drivers/usb/typec/mux/Kconfig
@@ -35,4 +35,12 @@ config TYPEC_MUX_INTEL_PMC
 	  control the USB role switch and also the multiplexer/demultiplexer
 	  switches used with USB Type-C Alternate Modes.
 
+config TYPEC_MUX_NB7VPQ904M
+	tristate "On Semiconductor NB7VPQ904M Type-C redriver driver"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  Say Y or M if your system has a On Semiconductor NB7VPQ904M Type-C
+	  redriver chip found on some devices with a Type-C port.
+
 endmenu
diff --git a/drivers/usb/typec/mux/Makefile b/drivers/usb/typec/mux/Makefile
index dda67e19b58b..76196096ef41 100644
--- a/drivers/usb/typec/mux/Makefile
+++ b/drivers/usb/typec/mux/Makefile
@@ -4,3 +4,4 @@ obj-$(CONFIG_TYPEC_MUX_FSA4480)		+= fsa4480.o
 obj-$(CONFIG_TYPEC_MUX_GPIO_SBU)	+= gpio-sbu-mux.o
 obj-$(CONFIG_TYPEC_MUX_PI3USB30532)	+= pi3usb30532.o
 obj-$(CONFIG_TYPEC_MUX_INTEL_PMC)	+= intel_pmc_mux.o
+obj-$(CONFIG_TYPEC_MUX_NB7VPQ904M)	+= nb7vpq904m.o
diff --git a/drivers/usb/typec/mux/nb7vpq904m.c b/drivers/usb/typec/mux/nb7vpq904m.c
new file mode 100644
index 000000000000..80e580d50129
--- /dev/null
+++ b/drivers/usb/typec/mux/nb7vpq904m.c
@@ -0,0 +1,529 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * OnSemi NB7VPQ904M Type-C driver
+ *
+ * Copyright (C) 2023 Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
+ */
+#include <linux/i2c.h>
+#include <linux/mutex.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/bitfield.h>
+#include <linux/of_graph.h>
+#include <drm/drm_bridge.h>
+#include <linux/usb/typec_dp.h>
+#include <linux/usb/typec_mux.h>
+#include <linux/usb/typec_retimer.h>
+#include <linux/gpio/consumer.h>
+#include <linux/regulator/consumer.h>
+
+#define NB7_CHNA		0
+#define NB7_CHNB		1
+#define NB7_CHNC		2
+#define NB7_CHND		3
+#define NB7_IS_CHAN_AD(channel) (channel == NB7_CHNA || channel == NB7_CHND)
+
+#define GEN_DEV_SET_REG			0x00
+
+#define GEN_DEV_SET_CHIP_EN		BIT(0)
+#define GEN_DEV_SET_CHNA_EN		BIT(4)
+#define GEN_DEV_SET_CHNB_EN		BIT(5)
+#define GEN_DEV_SET_CHNC_EN		BIT(6)
+#define GEN_DEV_SET_CHND_EN		BIT(7)
+
+#define GEN_DEV_SET_OP_MODE_MASK	GENMASK(3, 1)
+
+#define GEN_DEV_SET_OP_MODE_DP_CC2	0
+#define GEN_DEV_SET_OP_MODE_DP_CC1	1
+#define GEN_DEV_SET_OP_MODE_DP_4LANE	2
+#define GEN_DEV_SET_OP_MODE_USB		5
+
+#define EQ_SETTING_REG_BASE		0x01
+#define EQ_SETTING_REG(n)		(EQ_SETTING_REG_BASE + (n) * 2)
+#define EQ_SETTING_MASK			GENMASK(3, 1)
+
+#define OUTPUT_COMPRESSION_AND_POL_REG_BASE	0x02
+#define OUTPUT_COMPRESSION_AND_POL_REG(n)	(OUTPUT_COMPRESSION_AND_POL_REG_BASE + (n) * 2)
+#define OUTPUT_COMPRESSION_MASK		GENMASK(2, 1)
+
+#define FLAT_GAIN_REG_BASE		0x18
+#define FLAT_GAIN_REG(n)		(FLAT_GAIN_REG_BASE + (n) * 2)
+#define FLAT_GAIN_MASK			GENMASK(1, 0)
+
+#define LOSS_MATCH_REG_BASE		0x19
+#define LOSS_MATCH_REG(n)		(LOSS_MATCH_REG_BASE + (n) * 2)
+#define LOSS_MATCH_MASK			GENMASK(1, 0)
+
+#define AUX_CC_REG			0x09
+
+#define CHIP_VERSION_REG		0x17
+
+struct nb7vpq904m {
+	struct i2c_client *client;
+	struct gpio_desc *enable_gpio;
+	struct regulator *vcc_supply;
+	struct regmap *regmap;
+	struct typec_switch_dev *sw;
+	struct typec_retimer *retimer;
+
+	bool swap_data_lanes;
+	struct typec_switch *typec_switch;
+
+	struct drm_bridge bridge;
+
+	struct mutex lock; /* protect non-concurrent retimer & switch */
+
+	enum typec_orientation orientation;
+	unsigned long mode;
+	unsigned int svid;
+};
+
+static void nb7vpq904m_set_channel(struct nb7vpq904m *nb7, unsigned int channel, bool dp)
+{
+	u8 eq, out_comp, flat_gain, loss_match;
+
+	if (dp) {
+		eq = NB7_IS_CHAN_AD(channel) ? 0x6 : 0x4;
+		out_comp = 0x3;
+		flat_gain = NB7_IS_CHAN_AD(channel) ? 0x2 : 0x1;
+		loss_match = 0x3;
+	} else {
+		eq = 0x4;
+		out_comp = 0x3;
+		flat_gain = NB7_IS_CHAN_AD(channel) ? 0x3 : 0x1;
+		loss_match = NB7_IS_CHAN_AD(channel) ? 0x1 : 0x3;
+	}
+
+	regmap_update_bits(nb7->regmap, EQ_SETTING_REG(channel),
+			   EQ_SETTING_MASK, FIELD_PREP(EQ_SETTING_MASK, eq));
+	regmap_update_bits(nb7->regmap, OUTPUT_COMPRESSION_AND_POL_REG(channel),
+			   OUTPUT_COMPRESSION_MASK, FIELD_PREP(OUTPUT_COMPRESSION_MASK, out_comp));
+	regmap_update_bits(nb7->regmap, FLAT_GAIN_REG(channel),
+			   FLAT_GAIN_MASK, FIELD_PREP(FLAT_GAIN_MASK, flat_gain));
+	regmap_update_bits(nb7->regmap, LOSS_MATCH_REG(channel),
+			   LOSS_MATCH_MASK, FIELD_PREP(LOSS_MATCH_MASK, loss_match));
+}
+
+static int nb7vpq904m_set(struct nb7vpq904m *nb7)
+{
+	bool reverse = (nb7->orientation == TYPEC_ORIENTATION_REVERSE);
+
+	switch (nb7->mode) {
+	case TYPEC_STATE_SAFE:
+		regmap_write(nb7->regmap, GEN_DEV_SET_REG,
+			     GEN_DEV_SET_CHIP_EN |
+			     GEN_DEV_SET_CHNA_EN |
+			     GEN_DEV_SET_CHNB_EN |
+			     GEN_DEV_SET_CHNC_EN |
+			     GEN_DEV_SET_CHND_EN |
+			     FIELD_PREP(GEN_DEV_SET_OP_MODE_MASK,
+					GEN_DEV_SET_OP_MODE_USB));
+		nb7vpq904m_set_channel(nb7, NB7_CHNA, false);
+		nb7vpq904m_set_channel(nb7, NB7_CHNB, false);
+		nb7vpq904m_set_channel(nb7, NB7_CHNC, false);
+		nb7vpq904m_set_channel(nb7, NB7_CHND, false);
+		regmap_write(nb7->regmap, AUX_CC_REG, 0x2);
+
+		return 0;
+
+	case TYPEC_STATE_USB:
+		/*
+		 * Normal Orientation (CC1)
+		 * A -> USB RX
+		 * B -> USB TX
+		 * C -> X
+		 * D -> X
+		 * Flipped Orientation (CC2)
+		 * A -> X
+		 * B -> X
+		 * C -> USB TX
+		 * D -> USB RX
+		 *
+		 * Reversed if data lanes are swapped
+		 */
+		if (reverse ^ nb7->swap_data_lanes) {
+			regmap_write(nb7->regmap, GEN_DEV_SET_REG,
+				     GEN_DEV_SET_CHIP_EN |
+				     GEN_DEV_SET_CHNA_EN |
+				     GEN_DEV_SET_CHNB_EN |
+				     FIELD_PREP(GEN_DEV_SET_OP_MODE_MASK,
+						GEN_DEV_SET_OP_MODE_USB));
+			nb7vpq904m_set_channel(nb7, NB7_CHNA, false);
+			nb7vpq904m_set_channel(nb7, NB7_CHNB, false);
+		} else {
+			regmap_write(nb7->regmap, GEN_DEV_SET_REG,
+				     GEN_DEV_SET_CHIP_EN |
+				     GEN_DEV_SET_CHNC_EN |
+				     GEN_DEV_SET_CHND_EN |
+				     FIELD_PREP(GEN_DEV_SET_OP_MODE_MASK,
+						GEN_DEV_SET_OP_MODE_USB));
+			nb7vpq904m_set_channel(nb7, NB7_CHNC, false);
+			nb7vpq904m_set_channel(nb7, NB7_CHND, false);
+		}
+		regmap_write(nb7->regmap, AUX_CC_REG, 0x2);
+
+		return 0;
+
+	default:
+		if (nb7->svid != USB_TYPEC_DP_SID)
+			return -EINVAL;
+
+		break;
+	}
+
+	/* DP Altmode Setup */
+
+	regmap_write(nb7->regmap, AUX_CC_REG, reverse ? 0x1 : 0x0);
+
+	switch (nb7->mode) {
+	case TYPEC_DP_STATE_C:
+	case TYPEC_DP_STATE_E:
+		/*
+		 * Normal Orientation (CC1)
+		 * A -> DP3
+		 * B -> DP2
+		 * C -> DP1
+		 * D -> DP0
+		 * Flipped Orientation (CC2)
+		 * A -> DP0
+		 * B -> DP1
+		 * C -> DP2
+		 * D -> DP3
+		 */
+		regmap_write(nb7->regmap, GEN_DEV_SET_REG,
+			     GEN_DEV_SET_CHIP_EN |
+			     GEN_DEV_SET_CHNA_EN |
+			     GEN_DEV_SET_CHNB_EN |
+			     GEN_DEV_SET_CHNC_EN |
+			     GEN_DEV_SET_CHND_EN |
+			     FIELD_PREP(GEN_DEV_SET_OP_MODE_MASK,
+					GEN_DEV_SET_OP_MODE_DP_4LANE));
+		nb7vpq904m_set_channel(nb7, NB7_CHNA, true);
+		nb7vpq904m_set_channel(nb7, NB7_CHNB, true);
+		nb7vpq904m_set_channel(nb7, NB7_CHNC, true);
+		nb7vpq904m_set_channel(nb7, NB7_CHND, true);
+		break;
+
+	case TYPEC_DP_STATE_D:
+	case TYPEC_DP_STATE_F:
+		regmap_write(nb7->regmap, GEN_DEV_SET_REG,
+			     GEN_DEV_SET_CHIP_EN |
+			     GEN_DEV_SET_CHNA_EN |
+			     GEN_DEV_SET_CHNB_EN |
+			     GEN_DEV_SET_CHNC_EN |
+			     GEN_DEV_SET_CHND_EN |
+			     FIELD_PREP(GEN_DEV_SET_OP_MODE_MASK,
+					reverse ^ nb7->swap_data_lanes ?
+						GEN_DEV_SET_OP_MODE_DP_CC2
+						: GEN_DEV_SET_OP_MODE_DP_CC1));
+
+		/*
+		 * Normal Orientation (CC1)
+		 * A -> USB RX
+		 * B -> USB TX
+		 * C -> DP1
+		 * D -> DP0
+		 * Flipped Orientation (CC2)
+		 * A -> DP0
+		 * B -> DP1
+		 * C -> USB TX
+		 * D -> USB RX
+		 *
+		 * Reversed if data lanes are swapped
+		 */
+		if (nb7->swap_data_lanes) {
+			nb7vpq904m_set_channel(nb7, NB7_CHNA, !reverse);
+			nb7vpq904m_set_channel(nb7, NB7_CHNB, !reverse);
+			nb7vpq904m_set_channel(nb7, NB7_CHNC, reverse);
+			nb7vpq904m_set_channel(nb7, NB7_CHND, reverse);
+		} else {
+			nb7vpq904m_set_channel(nb7, NB7_CHNA, reverse);
+			nb7vpq904m_set_channel(nb7, NB7_CHNB, reverse);
+			nb7vpq904m_set_channel(nb7, NB7_CHNC, !reverse);
+			nb7vpq904m_set_channel(nb7, NB7_CHND, !reverse);
+		}
+		break;
+
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int nb7vpq904m_sw_set(struct typec_switch_dev *sw, enum typec_orientation orientation)
+{
+	struct nb7vpq904m *nb7 = typec_switch_get_drvdata(sw);
+	int ret;
+
+	ret = typec_switch_set(nb7->typec_switch, orientation);
+	if (ret)
+		return ret;
+
+	mutex_lock(&nb7->lock);
+
+	if (nb7->orientation != orientation) {
+		nb7->orientation = orientation;
+
+		ret = nb7vpq904m_set(nb7);
+	}
+
+	mutex_unlock(&nb7->lock);
+
+	return ret;
+}
+
+static int nb7vpq904m_retimer_set(struct typec_retimer *retimer, struct typec_retimer_state *state)
+{
+	struct nb7vpq904m *nb7 = typec_retimer_get_drvdata(retimer);
+	int ret = 0;
+
+	mutex_lock(&nb7->lock);
+
+	if (nb7->mode != state->mode) {
+		nb7->mode = state->mode;
+
+		if (state->alt)
+			nb7->svid = state->alt->svid;
+		else
+			nb7->svid = 0; // No SVID
+
+		ret = nb7vpq904m_set(nb7);
+	}
+
+	mutex_unlock(&nb7->lock);
+
+	return ret;
+}
+
+#if IS_ENABLED(CONFIG_OF) && IS_ENABLED(CONFIG_DRM_PANEL_BRIDGE)
+static int nb7vpq904m_bridge_attach(struct drm_bridge *bridge,
+				    enum drm_bridge_attach_flags flags)
+{
+	struct nb7vpq904m *nb7 = container_of(bridge, struct nb7vpq904m, bridge);
+	struct drm_bridge *next_bridge;
+
+	if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR))
+		return -EINVAL;
+
+	next_bridge = devm_drm_of_get_bridge(&nb7->client->dev, nb7->client->dev.of_node, 0, 0);
+	if (IS_ERR(next_bridge)) {
+		dev_err(&nb7->client->dev, "failed to acquire drm_bridge: %pe\n", next_bridge);
+		return PTR_ERR(next_bridge);
+	}
+
+	return drm_bridge_attach(bridge->encoder, next_bridge, bridge,
+				 DRM_BRIDGE_ATTACH_NO_CONNECTOR);
+}
+
+static const struct drm_bridge_funcs nb7vpq904m_bridge_funcs = {
+	.attach	= nb7vpq904m_bridge_attach,
+};
+
+static int nb7vpq904m_register_bridge(struct nb7vpq904m *nb7)
+{
+	nb7->bridge.funcs = &nb7vpq904m_bridge_funcs;
+	nb7->bridge.of_node = nb7->client->dev.of_node;
+
+	return devm_drm_bridge_add(&nb7->client->dev, &nb7->bridge);
+}
+#else
+static int nb7vpq904m_register_bridge(struct nb7vpq904m *nb7)
+{
+	return 0;
+}
+#endif
+
+static const struct regmap_config nb7_regmap = {
+	.max_register = 0x1f,
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
+enum {
+	NORMAL_LANE_MAPPING,
+	INVERT_LANE_MAPPING,
+};
+
+#define DATA_LANES_COUNT	4
+
+static const int supported_data_lane_mapping[][DATA_LANES_COUNT] = {
+	[NORMAL_LANE_MAPPING] = { 0, 1, 2, 3 },
+	[INVERT_LANE_MAPPING] = { 3, 2, 1, 0 },
+};
+
+static int nb7vpq904m_parse_data_lanes_mapping(struct nb7vpq904m *nb7)
+{
+	struct device_node *ep;
+	u32 data_lanes[4];
+	int ret, i, j;
+
+	ep = of_graph_get_endpoint_by_regs(nb7->client->dev.of_node, 1, 0);
+
+	if (ep) {
+		ret = of_property_count_u32_elems(ep, "data-lanes");
+		if (ret == -EINVAL)
+			/* Property isn't here, consider default mapping */
+			goto out_done;
+		if (ret < 0)
+			goto out_error;
+
+		if (ret != DATA_LANES_COUNT) {
+			dev_err(&nb7->client->dev, "expected 4 data lanes\n");
+			ret = -EINVAL;
+			goto out_error;
+		}
+
+		ret = of_property_read_u32_array(ep, "data-lanes", data_lanes, DATA_LANES_COUNT);
+		if (ret)
+			goto out_error;
+
+		for (i = 0; i < ARRAY_SIZE(supported_data_lane_mapping); i++) {
+			for (j = 0; j < DATA_LANES_COUNT; j++) {
+				if (data_lanes[j] != supported_data_lane_mapping[i][j])
+					break;
+			}
+
+			if (j == DATA_LANES_COUNT)
+				break;
+		}
+
+		switch (i) {
+		case NORMAL_LANE_MAPPING:
+			break;
+		case INVERT_LANE_MAPPING:
+			nb7->swap_data_lanes = true;
+			dev_info(&nb7->client->dev, "using inverted data lanes mapping\n");
+			break;
+		default:
+			dev_err(&nb7->client->dev, "invalid data lanes mapping\n");
+			ret = -EINVAL;
+			goto out_error;
+		}
+	}
+
+out_done:
+	ret = 0;
+
+out_error:
+	of_node_put(ep);
+
+	return ret;
+}
+
+static int nb7vpq904m_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct typec_switch_desc sw_desc = { };
+	struct typec_retimer_desc retimer_desc = { };
+	struct nb7vpq904m *nb7;
+	int ret;
+
+	nb7 = devm_kzalloc(dev, sizeof(*nb7), GFP_KERNEL);
+	if (!nb7)
+		return -ENOMEM;
+
+	nb7->client = client;
+
+	nb7->regmap = devm_regmap_init_i2c(client, &nb7_regmap);
+	if (IS_ERR(nb7->regmap)) {
+		dev_err(&client->dev, "Failed to allocate register map\n");
+		return PTR_ERR(nb7->regmap);
+	}
+
+	nb7->mode = TYPEC_STATE_SAFE;
+	nb7->orientation = TYPEC_ORIENTATION_NONE;
+
+	mutex_init(&nb7->lock);
+
+	nb7->enable_gpio = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_LOW);
+	if (IS_ERR(nb7->enable_gpio))
+		return dev_err_probe(dev, PTR_ERR(nb7->enable_gpio),
+				     "unable to acquire enable gpio\n");
+
+	nb7->vcc_supply = devm_regulator_get_optional(dev, "vcc");
+	if (IS_ERR(nb7->vcc_supply))
+		return PTR_ERR(nb7->vcc_supply);
+
+	nb7->typec_switch = fwnode_typec_switch_get(dev->fwnode);
+	if (IS_ERR(nb7->typec_switch))
+		return dev_err_probe(dev, PTR_ERR(nb7->typec_switch),
+				     "failed to acquire orientation-switch\n");
+
+	ret = nb7vpq904m_parse_data_lanes_mapping(nb7);
+	if (ret)
+		return ret;
+
+	ret = regulator_enable(nb7->vcc_supply);
+	if (ret)
+		dev_warn(dev, "Failed to enable vcc: %d\n", ret);
+
+	gpiod_set_value(nb7->enable_gpio, 1);
+
+	ret = nb7vpq904m_register_bridge(nb7);
+	if (ret)
+		return ret;
+
+	sw_desc.drvdata = nb7;
+	sw_desc.fwnode = dev->fwnode;
+	sw_desc.set = nb7vpq904m_sw_set;
+
+	nb7->sw = typec_switch_register(dev, &sw_desc);
+	if (IS_ERR(nb7->sw))
+		return dev_err_probe(dev, PTR_ERR(nb7->sw),
+				     "Error registering typec switch\n");
+
+	retimer_desc.drvdata = nb7;
+	retimer_desc.fwnode = dev->fwnode;
+	retimer_desc.set = nb7vpq904m_retimer_set;
+
+	nb7->retimer = typec_retimer_register(dev, &retimer_desc);
+	if (IS_ERR(nb7->retimer)) {
+		typec_switch_unregister(nb7->sw);
+		return dev_err_probe(dev, PTR_ERR(nb7->retimer),
+				     "Error registering typec retimer\n");
+	}
+
+	return 0;
+}
+
+static void nb7vpq904m_remove(struct i2c_client *client)
+{
+	struct nb7vpq904m *nb7 = i2c_get_clientdata(client);
+
+	typec_retimer_unregister(nb7->retimer);
+	typec_switch_unregister(nb7->sw);
+
+	gpiod_set_value(nb7->enable_gpio, 0);
+
+	regulator_disable(nb7->vcc_supply);
+}
+
+static const struct i2c_device_id nb7vpq904m_table[] = {
+	{ "nb7vpq904m" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, nb7vpq904m_table);
+
+static const struct of_device_id nb7vpq904m_of_table[] = {
+	{ .compatible = "onnn,nb7vpq904m" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, nb7vpq904m_of_table);
+
+static struct i2c_driver nb7vpq904m_driver = {
+	.driver = {
+		.name = "nb7vpq904m",
+		.of_match_table = nb7vpq904m_of_table,
+	},
+	.probe_new	= nb7vpq904m_probe,
+	.remove		= nb7vpq904m_remove,
+	.id_table	= nb7vpq904m_table,
+};
+
+module_i2c_driver(nb7vpq904m_driver);
+
+MODULE_AUTHOR("Dmitry Baryshkov <dmitry.baryshkov@linaro.org>");
+MODULE_DESCRIPTION("OnSemi NB7VPQ904M Type-C driver");
+MODULE_LICENSE("GPL");